The Avengers was produced by ABC Television, a contractor within the ITV network. After a merger in July 1968 ABC Television became Thames Television which continued production of the series, although it was still broadcast under the ABC name. By 1969 The Avengers was shown in more than 90 countries. The Avengers was the longest continuously running espionage series until 24. ITV produced a sequel series The New Avengers (1976–1977) with Patrick Macnee returning as John Steed, and two new partners.

The Avengers began with medical doctor, Dr David Keel (Ian Hendry), investigating the murder by a drug ring of his fiancée and office receptionist Peggy. A stranger named John Steed, who was investigating the ring, appeared and together they set out to avenge her death in the first two episodes. Afterwards, Steed asked Keel to partner him as needed to solve crimes.

The Avengers followed Hendry's Police Surgeon, in which he played police surgeon Geoffrey Brent.[2] While Police Surgeon did not last long, viewers praised Hendry. Hendry was considered the star of the new series, receiving top billing over Macnee, and Steed did not appear in two episodes.

As the series progressed, Steed's importance increased, and he carried the final episode solo. While Steed and Keel used wit while discussing crimes and dangers, the series also depicted the interplay — and often tension — between Keel's idealism and Steed's professionalism. As seen in the surviving episode "The Frighteners", Steed also had helpers among the population who provided information, similar to the "Baker Street Irregulars" of Sherlock Holmes.

The other regular in the first series was Carol Wilson (Ingrid Hafner), the nurse and receptionist who replaced the slain Peggy. Carol assisted Keel and Steed in cases, without being part of Steed's inner circle. Hafner had played opposite Hendry as a nurse in Police Surgeon.[2]

The series was shot on 405-line videotape using a multicamera setup. There was little provision for editing and virtually no location footage. As was standard practice at the time, videotapes of early episodes of The Avengers were reused. Of the first series, two complete episodes still exist, as 16 mm filmtelerecordings. One of the episodes remaining does not feature Steed. The first 15 minutes of the first episode also exists as a telerecording.

Production of the first series was cut short by a strike. By the time production could begin on the second series, Hendry had quit to pursue a film career. Macnee was promoted to star and Steed became the focus of the series, initially working with a rotation of three different partners. Dr Martin King (Jon Rollason), a thinly disguised rewriting of Keel, saw action in only three episodes produced from scripts written for the first series. King was intended to be a transitional character between Keel and Steed's two new female partners, but while the Dr. King episodes were shot first, they were shown out of production order in the middle of the season. The character was thereafter quickly and quietly dropped.

Nightclub singer Venus Smith (Julie Stevens) appeared in six episodes. She was a complete "amateur", meaning that she did not have any professional crime-fighting skills as did the two doctors. She was excited to be participating in a "spy" adventure alongside secret agent Steed (although at least one episode — "The Removal Men" — indicates she isn't always enthusiastic). Nonetheless, she appears to be attracted to him and their relationship appears similar to that later displayed between Steed and Tara King. Her episodes featured musical interludes showcasing her singing performances. The character of Venus underwent some revision during her run, adopting more youthful demeanour and dress.

The first episode broadcast in the second series had introduced the partner who would change the show into the format it is most remembered for. Honor Blackman played Dr. Cathy Gale, a self-assured, quick-witted anthropologist who was skilled in judo and had a passion for wearing leather clothes.[3] Widowed during the Mau Mau years in Kenya, she was the "talented amateur" who saw her aid to Steed's cases as a service to her nation. Gale was said to have been born 5 October 1930 at midnight, and was raised in Africa. Gale was early-to-mid 30s during her tenure, in contrast to female characters in similar series who tended to be younger.

Gale was unlike any female character seen before on British TV and became a household name. Reportedly, part of her charm came from the fact that her earliest appearances were episodes in which dialogue written for Keel was simply transferred to her. Said series script writer Dennis Spooner "there's the famous story of how Honor Blackman played Ian Hendry's part, which is why they stuck her in leather and such-it was so much cheaper than changing the lines!" [4]

Venus Smith did not return for the third series and Cathy Gale became Steed's only regular partner. The series established a level of sexual tension between Steed and Gale, but the writers were not allowed to go beyond flirting and innuendo. Despite this the relationship between Steed and Gale was progressive for 1962-63. In "The Golden Eggs" it is revealed that Gale lived in Steed's flat; her rent according to Steed was to keep the refrigerator well-stocked and to cook for him (she appears to do neither). However, this was said to be a temporary arrangement while Gale looked for a new home, and Steed was sleeping at a hotel.

During the first series there were hints Steed worked for a branch of British Intelligence, and this was expanded in the second series. Steed initially received orders from different superiors, including someone referred to as "Charles", and "One-Ten" (Douglas Muir). By the third series the delivery of Steed's orders was not depicted on screen or explained. In "The Nutshell" the secret organisation to which Steed belongs is shown, and it is Gale's first visit to their HQ.

Small references to Steed's background were occasionally made. In series three's "Death of a Batman" it was said that Steed was with I Corps in World War II, and in Munich in 1945. In series four episode "The Hour That Never Was" Steed goes to a reunion of his RAF regiment.

A film version of the series was in its initial planning stages by late 1963 after series three was completed. An early story proposal paired Steed and Gale with a male and female duo of American agents, to make the movie appeal to the American market. Before the project could gain momentum Blackman was cast opposite Sean Connery in Goldfinger, requiring her to leave the series.

During the Gale era Steed was transformed from a rugged trenchcoat-wearing agent into the stereotypical English gentleman, complete with Savile Row suit, bowler hat and umbrella with clothes later designed by Pierre Cardin. (The bowler and umbrella were full of tricks, including a sword hidden within the umbrella handle and a steel plate concealed in the hat.) These items were referred to in the French, German and Polish titles of the series, Chapeau melon et bottes de cuir ("Bowler hat and leather boots"), Mit Schirm, Charme und Melone ("With Umbrella, Charm and Bowler Hat") and Rewolwer i melonik ("A Revolver and a Bowler Hat"), respectively. With his impeccable manners, old world sophistication, and vintage automobiles, Steed came to represent the traditional Englishman of an earlier era.

By contrast his partners were youthful, forward-looking, and always dressed in the latest mod fashions. Gale's innovative leather outfits suited her many athletic fight scenes. Honor Blackman became a star in Britain with her black leather outfits and boots (nicknamed "kinky boots") and her judo-based fighting style. Macnee and Blackman even released a novelty song called "Kinky Boots". Some of the clothes seen in The Avengers were designed at the studio of John Sutcliffe who published the AtomAgefetish magazine.

Series script writer Dennis Spooner said that the series would frequently feature Steed visiting busy public places such as the main airport in London, without anyone else present in the scene. "'Can't you afford extras?' they'd ask. Well it wasn't like that; it's just that Steed had to be alone to be accepted-put him in a crowd and he sticks out like a sore thumb! Let's face it, with normal people he's weird. The trick to making him acceptable is never to show him in a normal world, just fighting villains who are odder than he is!" [4]

In 1965 the show was sold to United States network, the American Broadcasting Company (ABC). The Avengers became one of the first British series to be aired on prime time U.S. television. The ABC network paid the then-unheard of sum of $2 million for the first 26 episodes. The average budget for each episode was reportedly £56,000, high for the British industry. The fourth series aired in the U.S. from March to December 1966.

Previously The Avengers had been shot on 405-line videotape using a multicamera setup, with very little provision for editing and virtually no location footage. The U.S. deal meant that the producers could afford to start shooting the series on 35mm film. The use of film rather than videotape was essential, as British 405-line video was technically incompatible with the U.S. NTSC videotape format. Filmed productions were standard on U.S. prime time television at that time. The Avengers continued to be produced in monochrome.

The transfer to film meant that episodes would be shot using the single camera setup, giving the production greater flexibility. The videotaped episodes had looked cheap and studio bound. The use of film production and the single camera production style allowed more sophisticated visuals and camera angles and more outdoor location shots, all of which greatly improved the look of the series. As was standard on British television filmed production through the 1960s, all location work on series four was shot mute with the soundtrack created in post production. Dialogue scenes were filmed in the studio, leading to some jumps between location and studio footage.

New female partner Mrs. Emma Peel (Diana Rigg) debuted in this series, in October 1965. The name of the character derived from a comment by writers, during development, that they wanted a character with "man appeal". In an early attempt to incorporate this concept into the character's name, she was called "Samantha Peel", shortened to the awkward "Mantha Peel,"[5] Eventually the writers began referring to the idea by the verbal shorthand, "M. Appeal",[6] which gave rise to the character's ultimate name. Emma Peel, whose husband went missing while flying over the Amazon, retained the self-assuredness of Gale, combined with superior fighting skills, intelligence, and a contemporary fashion sense.

After more than 60 actresses had been auditioned, the first choice to play the role was Elizabeth Shepherd. However, after filming one and a half episodes, Shepherd was released. Her on-screen personality was deemed less interesting than that of Blackman's Gale and it was decided she simply wasn't right for the role. Another 20 actresses were auditioned before the show's casting director suggested that producers Brian Clemens and Albert Fennell check out a televised drama featuring the relatively unknown Rigg. Her screen test with Macnee showed that the two immediately worked well together, and a new era in Avengers history began.

A prologue was added to the beginning of all the fourth series episodes for the American transmissions. This was to clarify some initial confusion audiences had regarding the characters and their mission. In the opener, a waiter holding a champagne bottle falls dead onto a human-sized chessboard; a dagger protruding from a target on his back. Steed and Mrs. Peel (dressed in her trademark leather catsuit) walk up to the body as the voice over explains: "Extraordinary crimes against the people, and the state, have to be avenged by agents extraordinary. Two such people are John Steed, top professional, and his partner Emma Peel, talented amateur. Otherwise known as The Avengers." During this voice over, Steed pours two drinks from the wine bottle and Mrs. Peel replaces her gun in her boot. They clink glasses and depart together. Fade to black and then the opening titles proper begin.

In contrast to the Gale episodes, there was a lighter comic touch in Steed and Peel's interactions with each other and their reactions to other characters and situations. Earlier series had a harder tone, with the Gale era including some quite serious espionage dramas. This almost completely disappeared as Steed and Peel visibly enjoyed topping each other's witticisms. The layer of conflict with Gale-who on occasion openly resented being used by Steed, often without her permission-was absent from Steed's interaction with Peel. Also the sexual tension between Steed and Gale was not present with Peel. In both cases, the exact relationship between the partners was left ambiguous, although they seemed to have carte blanche to visit each other's homes whenever they pleased and it was not uncommon for scenes to suggest Steed had spent the night at Gale's or Peel's home, or vice-versa. Although nothing "improper" was displayed, the obviously much closer chemistry between Steed and Peel constantly suggests intimacy between the two.

In her fourth episode, "Death at Bargain Prices", Mrs. Peel takes an undercover job at a department store. Her uniform for promoting space-age toys is an elaborate leather catsuit plus silver boots, sash, and welder's gloves. The suit minus the silver accessories became her signature outfit which she wore, primarily for fight scenes, in early episodes, and in the titles. There was a fetishistic undercurrent in some episodes. In "A Touch of Brimstone" Mrs. Peel dressed in a dominatrix outfit of corset, laced boots and spiked collar to become the "Queen of Sin".

Peel's avant-garde fashions, featuring bold accents and high-contrast geometric patterns, emphasized her youthful, contemporary personality. She represented the modern England of the Sixties – just as Steed, with his vintage style and mannerisms, personified Edwardian era nostalgia. According to Macnee in his book The Avengers and Me, Rigg disliked wearing leather and insisted on a new line of fabric athletic wear for the 5th series. Alun Hughes, who had designed clothing for Diana Rigg's personal wardrobe, was suggested by the actress to design Emma Peel's "softer" new wardrobe.Pierre Cardin was brought in to design a new wardrobe for Macnee. In America, TV Guide ran a four-page photospread on Rigg's new "Emmapeeler" outfits (10–16 June 1967). Eight tight-fitting jumpsuits in a variety of bright colors were created using the stretch fabric crimplene.

Another memorable feature of the show from this point onwards was its automobiles. Steed's signature cars were vintage 1926–1928 Bentley racing or town cars, including Blower Bentleys and Bentley Speed Sixes (although, uniquely, in "The Thirteenth Hole" he drives a Vauxhall 30/98), while Peel drove a sporty Lotus Elan convertible which, like her clothes, emphasized her independence and vitality. During the first Peel series, each episode would end with a short, comedic scene of the duo leaving the scene of their most recent adventure in some unusual vehicle.

After one filmed series (of 26 episodes) in black and white, The Avengers began filming in colour for the fifth series in 1966. It would be three years before Britain's ITV network began full colour broadcasting.

This series was broadcast in the U.S. from January to May 1967. The American prologue of the previous series was rejigged for the colour episodes. It opened with the caption The Avengers In Color (required by ABC for colour series at that time). This was followed by Steed unwrapping the foil from a champagne bottle and Peel shooting the cork away. (Unlike the "chessboard" opening of the previous series, this new prologue was also included in UK broadcasts of the series.)

The first 16 episodes of the fifth series begin with Peel receiving a call-to-duty message from Steed: "Mrs. Peel, we're needed." Peel would be conducting her normal activities when she'd unexpectedly receive a message on a calling card or within a delivered gift, at which point Steed would suddenly appear (usually in her apartment). The messages would be delivered by Steed in increasingly bizarre ways as the series progressed: in a newspaper Peel had just bought, or on traffic lights while she was out driving. On one occasion Steed appeared on her television set, interrupting an old science-fiction movie (actually clips from their Year Four episode "The Cybernauts") to call her to work. Another way Steed contacted her was in the beginning of episode 13, "A Funny Thing Happened On The Way To The Station" when she enters her flat and sees a MeccanoPercy the Small Engine going around a circular track with a note on one of the train cars that says "Mrs. Peel" in bold letters, she then walks over to Steed who says "you're needed". At the start of "The Hidden Tiger" Peel is redecorating her apartment (wearing a jumpsuit and drinking champagne); she peels off a strip of wallpaper, revealing the words "Mrs Peel" painted on the wall beneath. She turns to see Steed in the apartment removing another strip of wallpaper, revealing "We're needed" painted underneath on another wall. In another instance Emma enters Steed's flat to find he has just fallen down the stairs, and he painfully gasps, "Mrs. Peel, you're needed." Often the episode's tag scene would return to the situation of the "Mrs. Peel, we're needed" scene. "The Hidden Tiger" returns to the partially redecorated apartment where Steed begins painting a love heart and arrow and the initials of two people on the wall, but paints over the initials when Peel sees his graffito. In "The Superlative Seven" the call to duty and the tag both involve a duck shooting situation where unexpected items fall from the sky after shots are fired.

The series also introduced a comic tag line caption to the episode title, using the format of "Steed [does this], Emma [does that]." For example "The Joker" had the opening caption: "Steed trumps an ace, Emma plays a lone hand".

The "Mrs. Peel, we're needed" scenes and the alternate tag lines were dropped after the first 16 episodes, after a break in production, for financial reasons. They were deemed by the U.K. networks as disposable if The Avengers was to return to ITV screens. (Dave Rogers' book The Avengers Anew lists a set for every Steed/Peel episode except "The Forget-Me-Knot".)

The series parodied its American contemporaries with episodes such as "The Girl From AUNTIE", "Mission... Highly Improbable" and "The Winged Avenger" (spoofing The Man from U.N.C.L.E., Mission: Impossible and Batman, respectively). The show still carried the basic format — Steed and his associate were charged with solving the problem in the space of a 50-minute episode, thus preserving the safety of 1960s Britain.

Comedy was evident in the names and acronyms of the organizations. For example, in "The Living Dead", two rival groups examine reported ghost sightings: FOG (Friends Of Ghosts) and SMOG (Scientific Measurement Of Ghosts). "The Hidden Tiger" features the Philanthropic Union for Rescue, Relief and Recuperation of Cats — PURRR — led by characters named Cheshire, Manx, and Angora.

The series also occasionally adopted a metafictional tone, coming close to breaking the fourth wall. In the series 5 episode "Something Nasty in the Nursery" Peel directly references the series' storytelling convention of having potentially-helpful sources of information killed off just before she or Steed arrive. This then occurs a few minutes later. In the tag scene for the same episode, Steed and Peel tell viewers - indirectly - to tune in next week.

For this series Diana Rigg's stunt double was stuntwoman Cyd Child, though stuntman Peter Elliot doubled for Rigg in a stunt dive in "The Bird Who Knew Too Much".

Rigg was initially unhappy with the way she was treated by the show's producers. During her first series she learned she was being paid less than the camera man. She demanded a raise which put her more on a par with her co-star, or she would leave the show. The producers gave in, thanks to the show's great popularity in the US.[7]

At the end of the fifth series in 1967, Rigg left to pursue other projects. This included following Honor Blackman to play a leading role in a James Bond film, in this case On Her Majesty's Secret Service.

When Diana Rigg left the series in October 1967, the British network executives decided that the current series formula, despite resulting in popular success, could not be pursued further. Thus they decided that a "return to realism" was appropriate for the sixth series (1968–69). Brian Clemens and Albert Fennel were replaced by John Bryce, producer of most of the Cathy Gale-era episodes.

Bryce had a difficult situation in hand. He had to find a replacement for Diana Rigg and shoot the first seven episodes of the new series, which were supposed to be shipped to America together with the last eight Emma Peel colour episodes.

Bryce signed his then-girlfriend, 20-year-old newcomer Linda Thorson, as the new female costar and chose the name "Tara King" for her character. Thorson played the role with more innocence in mind and at heart; and unlike the previous partnerships with Cathy and Emma, the writers allowed subtle hints of romance to blossom between Steed and King. King also differed from Steed's previous partners in that she was a fully fledged (albeit initially inexperienced) agent working for Steed's organisation; his previous partners had all been (in the words of the prologue used for American broadcasts of the first Rigg series) talented amateurs. Bryce wanted Tara to be blonde, so Thorson's brown hair was bleached. However the process badly damaged Thorson's hair, so she had to wear wigs for the first third of her episodes, until her own hair grew back. Her natural brown hair was not seen until the episode "All Done with Mirrors".

Production of the first seven episodes of the sixth series began. However financial problems and internal difficulties undermined Bryce's effort. He only managed to complete three episodes: "Invitation to a Killing" (a 90-minute episode introducing Tara King), "The Great, Great Britain Crime" (some of its original footage was reused in the 1969 episode "Homicide and Old Lace") and "Invasion of the Earthmen" (which survived relatively intact except for the scenes where Tara wears a brown wig.)

After a rough cut screening of these episodes to studio executives, Bryce was fired and Clemens and Fennel were summoned back. At their return, a fourth episode called "The Murderous Connection" was in its second day of production. After revising the script, it was renamed as "The Curious Case of the Countless Clues" and production was resumed. Production of the episode "Split!", a leftover script from the Emma Peel colour series, proceeded. Two completely new episodes were also shot: "Get-A-Way", and "Look (Stop Me If You've Heard This One) But There Were These Two Fellers".

Dennis Spooner said of the event that "Brian left The Avengers for about three episodes, someone took over, and when Brian came back, it was in a terrible state. He was faced with doing a rewrite on a film they'd already shot." The episode had a story error where Steed leaves for a destination. The villains then realise this and pursue him - yet arrive there before Steed does. It was fixed by having a character ask Steed 'What took you so long?', to which he replies 'I came the pretty way'. "You can only do that on The Avengers you see. It was just my favourite show to work on." [8]

Clemens and Fennel decided to film a new episode to introduce Tara King. This, the third episode filmed for the sixth series, was titled "The Forget-Me-Knot" and bade farewell to Emma Peel and introduced her successor, a trained but inexperienced agent named Tara King. It would be broadcast as the first episode of the sixth series. Tara debuts in dynamic style: when Steed is called to Headquarters, he is attacked and knocked down by trainee agent King who mistakes him for her training partner.

No farewell scenes for Emma Peel had been shot when Diana Rigg left the series. Rigg was recalled for "The Forget-Me-Knot", through which Emma acts as Steed's partner as usual. Rigg also filmed a farewell scene for Emma which appeared as the tag scene of the episode. It was explained that Emma's husband, Peter Peel, was found alive and rescued, and she left the British secret service to be with him. Emma visits Steed to say goodbye, and while leaving she passes Tara on the stairway giving the advice that "He likes his tea stirred anti-clockwise." Steed looks out the window as a departing Emma enters the Bentley driven by Peter - who from a distance seems to resemble Steed (and was played by Patrick Macnee, wearing a bowler hat and umbrella).

Bryce's original episode introducing Tara, "Invitation to a Killing", was revised as a regular 60-minute episode named "Have Guns Will Haggle". These episodes, together with "Invasion of the Earthmen" and the last eight Peel colour episodes, were shipped to America in February 1968.

For this series the government official who gave Steed his orders was depicted on screen. Mother, introduced in "The Forget-Me-Knot", is a man in a wheelchair. The role was taken by Patrick Newell who had played different roles in two earlier episodes, most recently in series five. Mother's headquarters would shift from place to place, including one episode where his complete office was on the top level of a double-decker bus. (Several James Bond films of the 1970s would make use of a similar gimmick for Bond's briefings.)

Added later as a regular was Mother's mute Amazonian assistant, Rhonda (Rhonda Parker). There was one appearance by an agency official code-named "Father", a blind older woman played by Iris Russell. (Russell had appeared in the series several times previously in other roles.) In one episode, "Killer", Steed is paired with Lady Diana Forbes Blakeney (Jennifer Croxton) while King is on holiday.

Scriptwriter Dennis Spooner later reflected on this series. "When I wrote "Look (Stop Me If You've Heard This One) But There Were These Two Fellers", that was definitely the last series. They were going to make no more, so in that series we went right over the top; we went really weird, because they knew there weren't going to be any more." [9]

Spooner said the series "worked because it became a parody on itself, almost. You can only do that so long." Overall he attributes the success of the show to its light approach. "We spoofed everything, we took Mission: Impossible, Bad Day at Black Rock, High Noon, The Dirty Dozen, The Birds... we took them all. The film buffs used to love it. There were always lines in it that people knew what we were talking about." [9]

Vehicle wise, Steed continued to drive vintage green Bentleys in the first seven episodes in production. His regular transport for the remainder of the series were two yellow Rolls-Royce cars. Mother also occasionally appeared in silver Rolls-Royces. Tara King drove an AC 428 and a Lotus Europa.

The revised series continued to be broadcast in America. The episodes with Linda Thorson as King proved to be highly rated in Europe and the UK. In the United States however, the ABC network which carried the series chose to air it opposite the number one show in the country at the time, Rowan and Martin's Laugh-In. Steed and King couldn't compete, and the show was cancelled in the US. Without this vital commercial backing, production could not continue in Britain either, and the series ended in May 1969. The final scene of the final episode ("Bizarre") has Steed and King, champagne glasses in hand, accidentally launching themselves into orbit aboard a rocket, as Mother breaks the fourth wall and says to the audience, "They'll be back!" before adding in shock, "They're unchaperoned up there!"

The 1961 series featured a jazz-influenced theme by John Dankworth. Library music was used sparsely as a soundtrack. Dankworth's theme music was reworked for the third series.

When Rigg joined the series new theme music by Laurie Johnson was introduced. This was issued on an LP, entitled The Shake.

Johnson re-scored the theme when Linda Thorson joined the series, adding a counter melody on trumpet. The new theme debuted in the closing titles of the episode "The Forget-Me-Knot", which introduced Thorson.

Johnson also provided incidental music. Owing to professional commitments in films, including Hot Millions, Johnson requested assistance from his keyboard player, Howard Blake, who scored some of the episodes of the final season. Blake composed additional music for other episodes which Johnson did not have time to complete.

Johnson subsequently collaborated with Clemens on other projects, including the theme for The New Avengers.

The production team changed during the series' long run, particularly between the third and fourth series, but the influence of Brian Clemens was felt throughout. He wrote the second episode and became the series' most prolific scriptwriter. Succeeding producers Leonard White and John Bryce, Julian Wintle became the producer of the 4th series with Brian Clemens credited as Associate Producer and Albert Fennell credited as "In charge of production". Series 5, made by A.B.C. Television Films, (which was created during the run up to Associated British Corporation and Associated-Redifussion forming Thames TV) Clemens and Fennell became co-producers, with Wintle as Executive Producer. For series 6, after its first producer John Bryce left, Clemens and Fennell returned as co-producers, early episodes also credit Julian Wintle as Consultant to the series and Philip Levene as Story Consultant.

Ray Austin became the fight arranger for series 4 and 5, introducing kung fu to the series. Later he became a prolific television director. Joe Dunne took over for series 6.

Although kinescopes of the second and third series were seen in Canada as early as 1965, the first three series of The Avengers were not broadcast on television in the United States. These series were shot in the studio on 405-line video using a multicamera setup. Episodes were often performed live to tape on the day they were to be transmitted and there was little provision for retakes. Seven episodes of the first series were actually performed live. As there was little opportunity for retakes, these early episodes were fraught with technical errors. The episode "Immortal Clay" features a visible camera shake. In "School for Traitors" Julie Stevens stumbles over her dialogue when introducing Steed to someone, prompting Macnee to ad lib a joke to cover the error.

In contrast 1960s US prime time drama television productions were shot on film using the single camera method. Retakes allowed obvious errors to be corrected in these productions. As they were originated on film, the editing techniques were far superior to those available for 405-line videotape. The 1965 sale of The Avengers to United States television prompted a change in production style to the single camera shooting method, originated on 35 mm film.

The more relaxed standards of British media would have required some moments to be censored in the U.S. In "Mr Teddy Bear" Steed strips down to his underwear for decontamination. In "Death Dispatch" Gale is seen wearing a black-lace brassiere.

The series' stunt man and stunt arranger Ray Austin expressed the opinion that the show's violence ultimately harmed its popular success in the United States. There The Avengers was given a late timeslot due to its violence. "They did that with the first Avengers here [in the U.S.], with Diana Rigg. They put us on at 11.30 pm on CBS [sic], because it was too violent." Austin goes on to explain that U.S. television follows a "different code". Austin said that on The Avengers "we were determined to do the show our way, the English way, and no one was going to stop us! And, indeed, no one did stop us. We never, never got to prime time. And it was our own faults, because we would not comply to the Midwest. That's where the money comes from in this country, nowhere else. Forget Los Angeles, forget New York-you have to aim for the Midwest. If the Midwest watches your show, you've made it." [10] In fact the first and second series of Emma Peel episodes mainly aired at 10.00 pm on ABC.[11] The final Rigg episodes and all the Linda Thorson episodes mainly ran at 7.30 pm, also on ABC.[12]

American censors objected to some content, in particular the episode "A Touch of Brimstone" which featured a modern day version of the Hellfire Club and climaxed with Emma being drugged and donning a skimpy corset costume with spiked collar and high heels to become the Queen of Sin, and being attacked with a whip by guest star Peter Wyngarde. The American broadcast network refused to air it.[13] In total five episodes from the first Emma Peel series were not initially broadcast by ABC.[14] These were: "A Surfeit of H2O", "Silent Dust" (which featured Emma being attacked with a horsewhip), "Quick-Quick Slow Death", "A Touch of Brimstone" and "Honey for the Prince" (in which Emma performed the dance of the seven veils), although they were seen in later syndicated repeats.

Earlier Cathy Gale and Venus Smith episodes had aired in Canada before the arrival of Mrs. Peel. U.S. audiences saw the 1962-1964 Gale and Smith episodes of the series for the first time in the early 1990s when they were broadcast on the A&E Network. No Keel episode of the series repeatedly was ever broadcast outside Britain, and even in the UK , only an episode "The Frighteners" (as part of a run of classic episodes on Channel 4 in early 1993, otherwise mostly consisting of Gale episodes).[15]

Six series of The Avengers were made between 1961 and 1969. There was an enforced break in filming and transmission towards the end of series five due to financial problems. Television researcher Andrew Pixley and authors Paul Cornell, Martin Day and Keith Topping in their book The Avengers Dossier: The Unauthorised and Unofficial Guide consider the last eight episodes produced after the break as constituting a short series six, and therefore count seven series in total. Within the internal production of The Avengers the last eight episodes were considered to be a continuation of series five.

All original videotapes from series one, two and three, which were shot on video, were wiped.

Only two complete episodes from the show's first series are known to exist, as 16mm film telerecordings. These are "The Frighteners", an extract of which is playing on a television in the film Quadrophenia, and "Girl on the Trapeze", which was found in the UCLA Film and Television Archive via an internet search of their on-line database. Part of the show's first episode was found in the United States. The footage is of the episode's first 21 minutes, up to the first commercial break.

All series two and three episodes survive as 16mm telerecordings. These have been released to DVD, as have all of the Emma Peel and Tara King episodes, which were shot on film. The two surviving complete Keel episodes, plus the remnant of the first episode, have also been released in the UK and US.

The sustained popularity of the Tara King episodes in France led to a 1975 French television advertisement for a brand of champagne with Thorson and Macnee reprising their roles. The advertisement's success spurred financing interest in France for new episodes of The Avengers.

The result was a new series, The New Avengers. Patrick Macnee reprised the role of Steed, with two new partners, Mike Gambit (Gareth Hunt) and Purdey (Joanna Lumley). It aired on ITV in the UK in 1976-1977, CTV in Canada, CBS in the United States (in 1978/79) and TF1 in France (series 1 in 1976-1977 and series 2 in 1979). The final four episodes were almost completely produced by Canadian interests and were filmed there. In some markets they carried the title The New Avengers in Canada.

A number of original novels based on the series were published in the 1960s.[20] The first by Douglas Enefer, published by Consul Books, was the only 60s novel to feature Cathy Gale. In the UK Panther books published four novels written by John Garforth, featuring Emma Peel in 1967, these were reprinted in the US by Berkley Medallion books, who, after Panther stopped publishing Avenger novels in the UK, continued publishing original novels of their own, one featuring Emma Peel & four featuring Tara King for the US market only, three by Keith Laumer in 1968 and two by Norman Daniels 1968/69. Berkely Medallion later re-printed all nine novels with new covers that featured photos of both Emma and Tara, regardless of which Avenger girl appeared in the novel. The two novels published by Hodder and Stoughton in 1965/66 were co-written by Patrick Macnee, making him one of the first actors to write licensed spin-off fiction of their own shows. The Macnee novels, deadline and dead duck, were reprinted in the UK by Titan Books in standard paperback in 1994 and in France by Huitieme Art (1995 & 1996). They were also published in the USA for the first time by TV Books in 1998. Titan reissued the books in trade paperback format (with the same covers) to coincide with the release of the feature film The Avengers.

There was a 1990 novel, Too Many Targets by John Peel, that featured all of Steed's partners except Venus Smith and Dr Martin King.
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A short story by Peter Leslie entitled "What's a Ghoul Like You Doing in a Place Like This?" appeared in The Television Crimebusters Omnibus, a hardback anthology edited by Peter Haining, first published by Orion in 1994.(This Steed and Tara story first appeared in the 1969 UK Avengers annual, from Atlas publications.)

Both of the Macnee/Leslie UK paperback titles were translated and published in Portugal in 1967 as 'Os Vingadores: O Dia Depois De Amanha' (deadline) and 'Os Vingadores: O Pato Morto' (dead duck) by Deaga. All four UK John Garforth Panther book paperbacks were translated and published by Roman in France (1967), a paperback omnibus edition was published in 1998 by Fleuve Noir. Three of the Garforth paperbacks were also translated and published by Heyne in Germany (1967/68) ('Heil Harris!' was not translated for obvious reasons.) and a German hardback omnibus edition of the three titles was published by Lichtenberg (1968), reprinted in paperback by Heyne in 1998. All four titles were also translated and published in Holland by Bruna (1967) and in Chile by Zig-Zag (1968).

The first UK Avengers comic strips [21] featuring Steed and Cathy Gale first appeared in regional TV listings magazines 'Look Westward' and 'The Viewer' from 14 September 1963 to 9 May 1964, (later in 1964, re-printed in the 'Manchester Evening News' newspaper.) this run consisted of 4 serials. Steed and Mrs Peel comic strips began in 'TV Comic' in issue 720, dated 2 October 1965, beginning after the TV debut of Emma Peel and ran until issue 771, dated 24 September 1966 (this run consisted of 10 serials plus one four page one off in TV Comic Holiday Special June 1966), when the rights were sold to publishers D.C. Thompson, where the next version of the strip appeared in issue 199, dated 10 December 1966, of 'Diana' the popular paper for girls, its run ended in issue 224, dated 2 June 1967, with art by Emilio Frejo and Juan Gonzalez Alacrojo, this run consisted of 8 serials. Earlier, 'The Growing Up of Emma Peel' comic strip had appeared in 'June and Schoolfriend' comic from issue 52, dated 29 January 1966, to issue 63, dated 16 April 1966, this had featured the adventures of 14 year old Emma Knight and was run concurent with the TV Comic strip and consisted of 11 instalments. The Avengers returned to TV comic issue 877, dated 5 October 1968, just after Tara King debuted on TV, the Tara & Steed strip continued until issue 1077, dated 5 August 1972, this run consisted of 28 serials plus one four page one off in TV Comic Holiday Special 1972. Also in 1966 Thorpe & Porter published a 68 page Avengers comic featuring Steed & Peel with original art by Mike Anglo and Mick Austin, this consisted of four 16 pages stories.

A few The Avengers-related comic books have been published in the USA. They are not named The Avengers because the rights to the names "Avengers" and "New Avengers" are held by Marvel Comics for use with their Avengers comics depicting a team of superheroes called The Avengers. Gold Key Comics published one issue of John Steed Emma Peel in 1968 (subtitled The Avengers on the Indicia page), which included two newly-coloured and reformatted The Avengers strips from "TV Comic". A three-issue miniseries entitled Steed and Mrs Peel appeared from 1990-1992 under the Eclipse Comics imprint, it featured a three part story, 'The Golden Game' in book 1-3, by Grant Morrison and a two part story, in book 2 & 3, 'A Deadly Rainbow' by Anne Caufield, both strips had art by Ian Gibson.

In the UK, where hard back annuals are traditionally produced for sale at Christmas, The Avengers first appeared in 'TV Crimebusters Annual' (1962) and featured a 7 page comic strip with Dr. David Keel titled 'The Drug Pedlar'. And Atlas publications produced three 'The Avengers' hard back Annuals for 1967, 1968 and 1969, which also featured original Avengers comic strips featuring Steed, Emma Peel and Tara King, as well as text stories.

The TV Comic Avengers strips and the 1966 Avengers comic and a few comic strips from the Annuals have been translated and published in Germany, Holland, France and Chile.

A stage version of The Avengers was produced in Britain in 1971, written by TV series veterans Brian Clemens and Terence Feely, and directed by Leslie Philips. It starred Simon Oates as Steed, Sue Lloyd as new partner Hannah Wild, and Kate O'Mara as villainess Madame Gerda. All three actors had played guest roles in the original series.[22]

A character named Hana Wilde (played by Charlotte Rampling) had essentially acted as Steed's partner in series five's "The Superlative Seven", an episode in which Emma Peel appears only briefly. According to John Peel in his overview of "The Superlative Seven", "Charlotte Rampling was rumoured to be grooming up to replace Diana Rigg in this story, but nothing ever came of that." [23]

The Avengers Radio series [24] was transmitted between 6 December 1971 and 28 December 1973 on Springbok Radio, the english language service of the South African Broadcasting Corporation (SABC), it was recorded at Sonovision Studios in Johannesberg, produced by Dave Gooden, the original TV scripts were adapted and directed by Tony Jay, for the 1st six months and Dennis Folbigge for the remainder. South Africa did not have national television until 1976.[25] The episodes were adapted from both Emma Peel and Tara King episodes, (with the Tara King character changed to Emma Peel throughout.) The Avengers were played by two British expatriate actors, Donald Monat as Steed and Diane Appleby as Mrs Peel, with Hugh Rouse as the tongue-in-cheek narrator. The stories were adapted into five episode serials under Tony Jay and six and seven episode serials under Dennis Folbigge, of approximately 15 minutes each (including adverts) and stripped across the week, Monday-Friday, on Springbok Radio.

Currently only 19 complete serials survive, all from reel-to-reel off-air recordings made by John Wright in 1972. Also the first 3 episodes of a re-make of Escape In Time currently exists, eps 1 & 2 are copies from the original Sonovision tapes, and ep 3 is from an off air recording, on audio cassette, made by Barbara Peterson, the rest of this serial is still missing.

These episodes are also known to have been transmitted in New York on station WBAI on 99.5 FM, from 1977 to the early 1990s.

Straight From The Shoulder (6 eps) (based on 'Invitation To A Killing')

Stop Me If You've Heard This (6) (based on 'Look, Stop Me If You've Heard This one etc..')

From Venus With Love (6 eps)

A Case of Interrogation (7 eps) (based on 'The Interrogators')

Too Many Oles (6 eps) (based on 'They Keep Killing Steed')

Train Of Events (6 eps) (based on 'A Funny Thing Happened on the way to the Station')

Escape in Time (eps 1-3 only)(a remake of the first serial broadcast in South Africa)

Copies from the original off-air recordings have been restored by Alan and Alys Hayes. And can be heard at their 'The Avengers Declassified' website and its sister website 'Avengers on the Radio'.
Many more serials were broadcast during its two year run on South African Radio, it is thought 83 serials were made & transmitted, but at present no other episodes are known to exist.

Plans for a motion picture based upon the series circulated during the 1960s, 1980s and 1990s, with Mel Gibson at one point being considered a front-runner for the role of Steed. Ultimately, the 1998 film starring Uma Thurman as Emma Peel and Ralph Fiennes as John Steed received poor reviews from critics and fans.

In Get Smart episode "Run, Robot, Run" (1968), evil British agents "Snead" and "Mrs Neal" are spoofs of Steed and Mrs Peel.

In an episode of Married... with Children, Al Bundy tries to buy an Avengers video featuring Mrs Peel, but receives a Tara King episode instead.

In Frasier episode "Radio Wars" Frasier's father says his sons were picked on as children for emulating Steed by wearing bowler hats. Daphne says she once dressed as Mrs. Peel in a skintight black leather catsuit for Halloween.

In an episode of Leverage Sophie and Hardison use the pseudonyms Emily Peel and Jonathan Steed.

Catherine Gale (played by Laura Putney) was the name of a CIA agent featured in the CBS series JAG in five episodes during seasons eight and nine (2002–2003): "Critical Condition" (8.01), "Need to Know" (8.07), "Pas de Deux" (8.23), "Shifting Sands" (9.02), and "Back In The Saddle" (9.06).[26]